What would Earth look like if we continue to burn all available fossil fuels, causing global temperatures to increase by 20 degrees Fahrenheit? That's the question University of Alaska Fairbanks researchers set out to answer by applying a new computer model that focusses on the Antarctic ice sheet.

The Antarctic ice sheet is larger than the U.S. with an average thickness of 6,200 feet and all by itself contains more than 50 percent of the world's fresh water. If it melted, sea levels would rise 160 feet and wash over existing coastlines. Their study made projections for up to 10,000 years in the future, but in as few as 1,000 years, more than half of this estimated melting could occur.

UAF's Parallel Ice Sheet Model (PISM) "was the perfect tool to find out whether human emissions are sufficient to render Earth ice free -- and unfortunately it turns out that they are," Anders Levermann, a researcher at the Potsdam Institute for Climate Impact Research in Germany, said in a news release.

If all available fossil fuels were burned it would release roughly 10,000 gigatons of carbon into the atmosphere, according to the researchers. One gigaton is equal to one billion tons. This amount of carbon would be enough to trap enough radiation to increase the planet's temperature by 20 degrees Fahrenheit, enough to melt the Antarctic ice sheet, according to UAF's computer program.

"The future evolution of the global sea level is mainly determined by the melting of the big ice sheets on Greenland and Antarctica," Levermann explained. "If we want to properly protect our cities, we need to know how these ice sheets evolve. Models like PISM are the only chance we have to understand future sea-level rise."

PISM was built to answer "what-if" scenarios for various ice sheets and glaciers. It can make projections over a time span of 100,000 years into the future and the past, by incorporating factors such as ice thickness and temperature, the weight of the ice and how fast the ice flows as gravity slowly pulls it downhill.

"The equations are a way to say precisely how the parts of an ice sheet work and how each of these pieces is connected to all the others," Ed Bueler, a UAF associate professor and one of the computer programmers, said in a statement. "Once you have the equations, you can make predictions."

While other computer models can take decades to answer one problem, PISM can answer a wide variety of questions in a timely manner. The researchers post their findings online, so that others can use it freely and provide additional feedback.